1. Field of the Invention
This invention relates generally to lock assemblies incorporating barrel locks, and is concerned in particular with the self retention of the barrel locks in the lock assemblies when in the unlocked state. Such lock assemblies are widely employed by public utilities to secure meters, supply conduits, etc. against unauthorized access.
2. Description of the Prior Art
The metering mechanism of a conventional utility meter is typically enclosed within a transparent cover removably mounted to the lid of a box-shaped housing. The cover and lid have confronting circular rims which are held in an axially aligned abutting relationship by a split retaining ring in combination with a barrel lock.
The split retaining ring has a generally channel-shaped side wall curving from one end containing an internal bushing to another end provided with a cylindrical external collar. The internal bushing and external collar comprise components of a lock assembly configured for use with a barrel lock. The retaining ring may either be resiliently deformable or hinged to accommodate its adjustment between an enlarged condition for installation on and removal from the confronting meter rims, and an installed constricted condition which radially and axially confines the confronting meter rims within the channel-shaped ring wall. When the ring is in its enlarged condition, the internal bushing and the external collar on its opposite ends are out of alignment and lie on parallel axes. When the ring is constricted to its installed condition, the opposite ring ends are brought together with the internal bushing and external collar aligned coaxially and in communication with each other. The barrel lock is then inserted into the communicating coaxially aligned collar and bushing to retain the ring in its constricted condition. The barrel lock has radially shiftable locking balls which coact in interengagement with an inner recess in the internal bushing to prevent unauthorized removal of the lock. The locking balls are urged radially outwardly by a spring loaded plunger. A specially designed key is employed to axially retract the plunger allowing the locking balls to retract radially into the lock barrel to thereby accommodate insertion and removal of the lock into and out of its locked position. Barrel locks are similarly employed to releasably assemble mating components in dead bolt assemblies, cap and plug locks, etc.
There are several problems with the manner in which barrel locks are currently employed. In many cases, the barrel locks are supplied as separate components which must be assembled on site. This complicates installation and can lead to locks being misplaced or lost. Secondly, a key must be employed to assemble the locks with their associated lock components. This requires widespread distribution of keys to installation personnel, which in turn increases the danger that keys will be lost or stolen, thereby seriously compromising overall system security.
In order to counteract these problems, several lock suppliers, including the assignee of the present invention, have sought to develop lock assemblies with barrel locks that are preassembled and temporarily retained in a retracted unlocked position, with only an externally applied force being required to advance the locks into the locked position.
A decided drawback with these arrangements, however, has been the perceived need on the part of those skilled in the art to specially machine and configure the lock barrels to mechanically interengage in the unlocked position with other components of the lock assembly. In some cases, the other lock components are xe2x80x9cextraxe2x80x9d, i.e., in addition to those conventionally employed in standard lock assemblies.
Thus, at the manufacturing level, costs are disadvantageously increased by the need to specially machine and configure the lock barrels, and/or to incorporate extra components into the lock assembly.
At the user level, where conventional lock assemblies and barrel locks are already in use, the introduction of barrel locks with specially configured barrels requires both types of locks to be maintained in inventory for use by installation and maintenance personnel, thus disadvantageously complicating the overall administration of a security system.
The present invention proceeds from the realization that contrary to conventional wisdom, it is not necessary to specially configure the lock barrels, or to employ extra lock components, in order to temporarily retain the barrel locks in a retracted unlocked position. Instead, this function can be assigned to the locking balls of a standard barrel lock acting in concert with an appropriately configured and positioned internal recess in a standard lock collar. By doing do, manufacturing costs are not adversely impacted, and users are not saddled with the problems associated with maintaining and employing an inventory of different barrel locks.
These and other objectives and advantages of the present invention will become more apparent as the description proceeds with the aid of the accompanying drawings, wherein: